1. Field of the Invention
The present invention relates generally to printing presses and more particularly to a device and method for cleaning one or more selected portions of a cylinder of a printing press.
2. Background Information
Offset lithographic printing presses, for example, have a blanket cylinder for transferring images from a printing cylinder to a web of material, such as paper. Blankets on the blanket cylinder typically have a rubber outer print layer, while printing plates on the printing plate cylinder typically are made of metal.
Especially after continued use, blanket and printing plate cylinders accumulate foreign matter such as ink, lint, dust, clay, dirt and the like which should be removed by cleaning. Lack of proper cleaning can lead to poor print quality and reduce press productivity. Many times, only a small area of a blanket or printing plate needs to be cleaned. While various cleaning methods and devices are known, many are not capable of doing spot-cleaning. Those that are capable of spot-cleaning are often too slow.
U.S. Pat. No. 5,257,578 describes an automatic cleaning device using a brush roller for cleaning blanket cylinders in a web fed offset lithographic printing press. The device is not capable of doing spot cleaning, however.
German Patent Document No. DE-OS 34 10 376 and its equivalent U.S. Pat. No. 4,499,827 describe a cleaning device for doing spot-cleaning in which a small cleaning element must be moved transversely across a cylinder to a specific location to be spot cleaned. The positioning of the cleaning element is time-consuming.
U.S. Pat. No. 5,020,433 describes a cleaning device in which subsets of a plurality of scraper, or doctor, blades may be selectively positioned for cleaning specific areas of a plate and a blanket cylinder in an offset printing machine. Scraper, or doctor, blades do not work well for cleaning ink residues on blanket, for example, cylinders as the blades tend to smear rather than remove the ink.
An object of the present invention is to provide a device and method for selectively, or spot, cleaning a surface of a printing press cylinder.
The present invention provides an apparatus for cleaning one or more selected portions of a surface of a cylinder of a printing press, the apparatus comprising:
a plurality of brush elements disposed adjacent one another opposite the surface of the cylinder; and
a device for selectively moving one or more of the plurality of brushes to contact the one or more selected portions of the surface of the cylinder so as to clean the one or more selected portions.
Each of the brush elements may include a brush wheel, which may be rotated about a respective axis.
The device for selectively moving one or more of the plurality of brush elements may include a pneumatic, a hydraulic, a lever, a cam, an electrical and/or a magnetic actuator.
The device for selectively moving one or more of the plurality of brush elements may be controlled using a logic used to zone-control ink fountains of the printing press.
The brush elements may be movable along a part of the surface so as to improve the cleaning and/or to clean an area of the surface at a gap between adjacent ones of the brush elements.
An apparatus according to the present invention may include a spray device controllable to selectively deliver a cleaning liquid to the one or more of the plurality of brushes or the one or more selected portions of the surface.
The present invention also provides an apparatus for cleaning one or more selected portions of a surface of a cylinder of a printing press, the apparatus comprising:
a washer cloth disposed opposite the surface of the cylinder; and
a device for selectively moving one or more areas of the cloth to contact the surface of the cylinder so as to clean the one or more selected portions of the surface.
The device for selectively moving one or more areas of the cloth may include a plurality of adjacent air bladders capable of being selectively actuated.
The device for selectively moving one or more areas of the cloth may include a plurality of adjacent pushing elements capable of being selectively actuated.
The plurality of adjacent pushing elements may be capable of being selectively actuated using a logic for zone-controlling ink fountains of the printing press.
Each of the brush elements may include a pneumatic, a hydraulic, a lever, a cam, an electrical and/or a magnetic actuator.
An apparatus according to the present invention may include a spray device controllable to selectively deliver a cleaning liquid to the one or more areas of the cloth or the one or more selected portions of the surface.
The spray device may include a plurality of spray nozzles capable of being independently actuated in concert with the moving of the one or more of the areas of the cloth to contact the surface of the cylinder.
The present invention also provides a method for cleaning one or more selected portions of a surface of a cylinder of a printing press, the method comprising:
providing a segmented cleaning device opposite a surface of the cylinder, the segmented cleaning device including at least one of a segmented washer cloth device and a plurality of brush elements disposed adjacent one; and
selectively moving one or more segments of the cleaning device into contact with the one or more selected portions of the surface of the cylinder so as to clean the one or more selected portions of the surface.
The segmented washer cloth device may include a washer cloth and a plurality of adjacent air bladders capable of being selectively actuated or a plurality of adjacent pushing elements capable of being selectively actuated so as to move one or more areas of the washer cloth into contact with the one or more selected portions of the surface of the cylinder.
The selectively moving the one or more of the segments may be performed using a pneumatic, a hydraulic, a lever, a cam, an electrical and/or a magnetic actuator.
The device for selectively moving one or more segments of the cleaning device may be controlled using a logic used to zone-control ink fountains of the printing press.
The cylinder cleaned may be a blanket cylinder or a printing plate cylinder.
The present invention enables spot cleaning, as well as full cylinder-width cleaning and variable partial, for example one third-width, cleaning of a surface of printing press cylinder.